Tracking data processing in an application carried out on a distributed computing system

ABSTRACT

Methods, systems, and products are disclosed for tracking data processing in an application carried out on a distributed computing system, the distributed computing system including a plurality of computing nodes connected through a data communications network, the application carried out by a plurality of pluggable processing components installed on the plurality of computing nodes, the pluggable processing components including a pluggable processing provider component and a pluggable processing consumer component, that include: identifying, by the provider component, data satisfying predetermined processing criteria, the criteria specifying that the data is relevant to processing provided by the consumer component; passing, by the provider component, the data to the next pluggable processing component in the application for processing, including maintaining access to the data; receiving, by the consumer component, the data during execution of the application; and sending, by the consumer component, a receipt indicating that the consumer component received the data.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention is data processing, or, more specifically,methods, apparatus, and products for tracking data processing in anapplication carried out on a distributed computing system.

2. Description of Related Art

The development of the EDVAC computer system of 1948 is often cited asthe beginning of the computer era. Since that time, computer systemshave evolved into extremely complicated devices. Today's computers aremuch more sophisticated than early systems such as the EDVAC. Computersystems typically include a combination of hardware and softwarecomponents, application programs, operating systems, processors, buses,memory, input/output devices, and so on. As advances in semiconductorprocessing and computer architecture push the performance of thecomputer higher and higher, more sophisticated computer software hasevolved to take advantage of the higher performance of the hardware,resulting in computer systems today that are much more powerful thanjust a few years ago.

Parallel computing is an area of computer technology that hasexperienced advances. Parallel computing is the simultaneous executionof the same task (split up and specially adapted) on multiple processorsin order to obtain results faster. Parallel computing is based on thefact that the process of solving a problem usually can be divided intosmaller tasks, which may be carried out simultaneously with somecoordination.

Parallel computers execute applications that include both parallelalgorithms and serial algorithms. A parallel algorithm can be split upto be executed a piece at a time on many different processing devices,and then put back together again at the end to get a data processingresult. Some algorithms are easy to divide up into pieces. Splitting upthe job of checking all of the numbers from one to a hundred thousand tosee which are primes could be done, for example, by assigning a subsetof the numbers to each available processor, and then putting the list ofpositive results back together. In this specification, the multipleprocessing devices that execute the algorithms of an application arereferred to as ‘compute nodes.’ A parallel computer is composed ofcompute nodes and other processing nodes as well, including, forexample, input/output (‘I/O’) nodes, and service nodes.

Parallel algorithms are valuable because it is faster to perform somekinds of large computing tasks via a parallel algorithm than it is via aserial (non-parallel) algorithm, because of the way modern processorswork. It is far more difficult to construct a computer with a singlefast processor than one with many slow processors with the samethroughput. There are also certain theoretical limits to the potentialspeed of serial processors. On the other hand, every parallel algorithmhas a serial part and so parallel algorithms have a saturation point.After that point adding more processors does not yield any morethroughput but only increases the overhead and cost.

Parallel algorithms are designed also to optimize one more resource—thedata communications requirements among the nodes of a parallel computer.There are two ways parallel processors communicate, shared memory ormessage passing. Shared memory processing needs additional locking forthe data and imposes the overhead of additional processor and bus cyclesand also serializes some portion of the algorithm.

Message passing processing uses high-speed data communications networksand message buffers, but this communication adds transfer overhead onthe data communications networks as well as additional memory need formessage buffers and latency in the data communications among nodes.Designs of parallel computers use specially designed data communicationslinks so that the communication overhead will be small but it is theparallel algorithm that decides the volume of the traffic.

Many data communications network architectures are used for messagepassing among nodes in parallel computers. Compute nodes may beorganized in a network as a ‘torus’ or ‘mesh,’ for example. Also,compute nodes may be organized in a network as a tree. A torus networkconnects the nodes in a three-dimensional mesh with wrap around links.Every node is connected to its six neighbors through this torus network,and each node is addressed by its x,y,z coordinate in the mesh. A torusnetwork lends itself to point to point operations. In a tree network,the nodes typically are connected into a binary tree: each node has aparent, and two children (although some nodes may only have zerochildren or one child, depending on the hardware configuration). Incomputers that use a torus and a tree network, the two networkstypically are implemented independently of one another, with separaterouting circuits, separate physical links, and separate message buffers.A tree network provides high bandwidth and low latency for certaincollective operations, message passing operations where all computenodes participate simultaneously, such as, for example, an allgather.

Many applications that execute in these parallel computing systems areeach composed of a plurality of individual, reusable softwarecomponents. For example, a facial recognition software application maybe composed of one reusable software component that performs imagepreprocessing, another reusable software component that performs faceposition detection within the processed image, still another reusablesoftware component that measures facial features, and so on.

SUMMARY OF THE INVENTION

Methods, systems, and products are disclosed for tracking dataprocessing in an application carried out on a distributed computingsystem. The distributed computing system includes a plurality ofcomputing nodes connected for data communications through a datacommunications network. The application is carried out by a plurality ofpluggable processing components installed on the plurality of computingnodes. The pluggable processing components include a pluggableprocessing provider component and a pluggable processing consumercomponent. Tracking data processing in an application carried out on adistributed computing system includes: identifying, by the pluggableprocessing provider component, data satisfying predetermined processingcriteria, the predetermined processing criteria specifying that the datais relevant to processing provided by the pluggable processing consumercomponent; passing, by the pluggable processing provider component, thedata to the next pluggable processing component in the application forprocessing, including maintaining access to the data; receiving, by thepluggable processing consumer component, the data during execution ofthe application; and sending, by the pluggable processing consumercomponent, a receipt indicating that the pluggable processing consumercomponent received the data.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescriptions of exemplary embodiments of the invention as illustrated inthe accompanying drawings wherein like reference numbers generallyrepresent like parts of exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary distributed computing system fortracking data processing in an application carried out on thedistributed computing system according to embodiments of the presentinvention.

FIG. 2 sets forth a block diagram of an exemplary compute node useful ina distributed computing system capable of tracking data processing in anapplication carried out on the distributed computing system according toembodiments of the present invention.

FIG. 3A illustrates an exemplary Point To Point Adapter useful indistributed computing systems capable of tracking data processing in anapplication carried out on the distributed computing system according toembodiments of the present invention.

FIG. 3B illustrates an exemplary Global Combining Network Adapter usefulin distributed computing systems capable of tracking data processing inan application carried out on the distributed computing system accordingto embodiments of the present invention.

FIG. 4 sets forth a line drawing illustrating an exemplary datacommunications network optimized for point to point operations useful indistributed computing systems capable of tracking data processing in anapplication carried out on the distributed computing system inaccordance with embodiments of the present invention.

FIG. 5 sets forth a line drawing illustrating an exemplary datacommunications network optimized for collective operations useful indistributed computing systems capable of tracking data processing in anapplication carried out on the distributed computing system inaccordance with embodiments of the present invention.

FIG. 6 sets forth a flow chart illustrating an exemplary method fortracking data processing in an application carried out on a distributedcomputing system according to embodiments of the present invention.

FIG. 7 sets forth a flow chart illustrating a further exemplary methodfor tracking data processing in an application carried out on adistributed computing system according to embodiments of the presentinvention.

FIG. 8 sets forth a flow chart illustrating a further exemplary methodfor tracking data processing in an application carried out on adistributed computing system according to embodiments of the presentinvention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary methods, apparatus, and computer program products for trackingdata processing in an application carried out on a distributed computingsystem according to embodiments of the present invention are describedwith reference to the accompanying drawings, beginning with FIG. 1. FIG.1 illustrates an exemplary distributed computing system for trackingdata processing in an application carried out on the distributedcomputing system according to embodiments of the present invention. Thedistributed computing system of FIG. 1 includes a parallel computer(100), non-volatile memory for the computer in the form of data storagedevice (118), an output device for the computer in the form of printer(120), and an input/output device for the computer in the form ofcomputer terminal (122). Parallel computer (100) in the example of FIG.1 includes a plurality of compute nodes (102).

In the example of FIG. 1, the compute nodes (102) operate to execute anapplication (200) that is carried out using a plurality of pluggableprocessing components (210). A pluggable processing component is asoftware module, specifically a set of computer program instructions,that when executed performs a particular task that is a logical,discrete, reusable building block for more complex software systems.That is, a software developer may create a pluggable processingcomponent to perform a specific task within broader software systemsthat the software developer can reuse from one system to another. Theprocessing components are referred to as ‘pluggable’ because thesecomponents may be plugged together in different ways to form a varietyof software applications.

For an example application, consider a plurality of pluggable processingcomponents that implement a facial recognition system and that operateas follows: An image identification component provides an image to apreprocessing component, which cleans up the image by removing visualnoise attributable to the camera capturing the image or other visualnoise or aberrations. The preprocessing component provides thepreprocessed image to a face detection component that identifies aperson's face within the image. The face detection component in turnprovides the image and the location of the face in the image to analignment component that determines the head's position, size, and pose.The alignment component then provides the image and the alignment datato a measurement component that measures the curves of the face on asub-millimeter or microwave scale and creates a template that describesthe features of the face in the image. A representation componentreceives the template from the measure component and translates thetemplate into a set of codes that represent the features of the face inthe image. The representation component then provides the set of codesto a matching component that compares the set of codes with codesrepresenting faces of known persons in a database to identify a match.When performing identity verification, a candidateverification/identification component receives an identifier for amatching face in the database and compares information associated withthe matched face in the database with information provided by the personwhose face is captured for facial recognition. When performingidentification, the candidate verification/identification componentreceives an identifier for a matching face in the database and providessystem administrators with the information associated with the matchedface in the database.

The pluggable processing components (210) of FIG. 1 include pluggableprocessing provider components and pluggable processing consumercomponents. A pluggable processing provider component is a pluggableprocessing component that provides data to other pluggable processingcomponents for consumption. A pluggable processing consumer component isa pluggable processing component that received data from other pluggableprocessing components for further data processing. Readers will notethat a particular pluggable processing component may operate as both aprovider component and a consumer component concurrently. For example,consider again the exemplary facial recognition system described above.The image preprocessing component is a consumer component with respectto the image identification component, while concurrently operating as aprovider component with respect to the face detection component.

In the example of FIG. 1, both the pluggable processing providercomponents and the pluggable processing consumer components operategenerally for tracking data processing in an application carried out ona distributed computing system according to embodiments of the presentinvention. The pluggable processing provider components operategenerally for tracking data processing in an application carried out ona distributed computing system according to embodiments of the presentinvention by: identifying data satisfying predetermined processingcriteria, the predetermined processing criteria specifying that the datais relevant to processing provided by the pluggable processing consumercomponent; and passing the data to the next pluggable processingcomponent in the application for processing, including maintainingaccess to the data. The pluggable processing consumer components operategenerally for tracking data processing in an application carried out ona distributed computing system according to embodiments of the presentinvention by: receiving the data during execution of the application;and sending a receipt indicating that the pluggable processing consumercomponent received the data.

The pluggable processing provider components may also operate generallyfor tracking data processing in an application carried out on adistributed computing system according to embodiments of the presentinvention by: receiving, from the pluggable processing consumercomponent, the receipt indicating that the pluggable processing consumercomponent received the data; and administering the data in response toreceiving the receipt. Because a pluggable processing provider componentmay not always receive the receipt from the consumer component, thepluggable processing provider components may operate generally fortracking data processing in an application carried out on a distributedcomputing system according to embodiments of the present invention by:determining that the pluggable processing provider component did notreceive the receipt within a predefined time period; and performing oneor more corrective actions in response to not receiving the receiptwithin a predefined time period.

Also installed on the plurality of compute nodes (102) of FIG. 1 is asystem administrative component (702). The system administrativecomponent (702) of FIG. 1 is a set of computer program instructions formanaging the plurality of pluggable processing components carrying outthe application (200). In some embodiments, the pluggable processingconsumer components may not have enough information about the providercomponent to send a receipt directly to the provider component. In suchembodiments, the system administrative component (702) may operategenerally for tracking data processing in the application (200) carriedout on a distributed computing system according to embodiments of thepresent invention by: receiving, from the pluggable processing consumercomponent, the receipt indicating that the pluggable processing consumercomponent received the data; and sending, to the pluggable processingprovider component, the receipt indicating that the pluggable processingconsumer component received the data. The pluggable processing providercomponent may in turn operate for tracking data processing in theapplication (200) carried out on a distributed computing systemaccording to embodiments of the present invention by: receiving, fromthe system administrative component, the receipt indicating that thepluggable processing consumer component received the data; andadministering the data in response to receiving the receipt.

The execution configuration for the pluggable processing components(210) may change during or between periods in which the pluggableprocessing components (210) are executed on the compute nodes (102). Inthe example of FIG. 1, each pluggable processing component (210) may beexecuted on a different compute node (102). In some configurations,however, compute nodes (102) may support multiple pluggable processingcomponents (210). During execution, a service node may move onepluggable processing component (210) from one compute node (102) toanother, or multiple pluggable processing components (210) may becollapsed for execution on one compute node (102) from multiple computenodes (102). The service node may move a pluggable processing component(210) from one node to another by transferring the executable version ofthe pluggable processing component (210) along with processing stateinformation such as memory contents, cache contents, processorregisters, data, and so on from one compute node to another.

The compute nodes (102) are coupled for data communications by severalindependent data communications networks including a Joint Test ActionGroup (‘JTAG’) network (104), a global combining network (106) which isoptimized for collective operations, and a torus network (108) which isoptimized point to point operations. The global combining network (106)is a data communications network that includes data communications linksconnected to the compute nodes so as to organize the compute nodes as atree. Each data communications network is implemented with datacommunications links among the compute nodes (102). The datacommunications links provide data communications for parallel operationsamong the compute nodes of the parallel computer. The links betweencompute nodes are bi-directional links that are typically implementedusing two separate directional data communications paths.

In addition, the compute nodes (102) of parallel computer are organizedinto at least one operational group (132) of compute nodes forcollective parallel operations on parallel computer (100). Anoperational group of compute nodes is the set of compute nodes uponwhich a collective parallel operation executes. Collective operationsare implemented with data communications among the compute nodes of anoperational group. Collective operations are those functions thatinvolve all the compute nodes of an operational group. A collectiveoperation is an operation, a message-passing computer programinstruction that is executed simultaneously, that is, at approximatelythe same time, by all the compute nodes in an operational group ofcompute nodes. Such an operational group may include all the computenodes in a parallel computer (100) or a subset all the compute nodes.Collective operations are often built around point to point operations.A collective operation requires that all processes on all compute nodeswithin an operational group call the same collective operation withmatching arguments. A ‘broadcast’ is an example of a collectiveoperation for moving data among compute nodes of an operational group. A‘reduce’ operation is an example of a collective operation that executesarithmetic or logical functions on data distributed among the computenodes of an operational group. An operational group may be implementedas, for example, an MPI ‘communicator.’

‘MPI’ refers to ‘Message Passing Interface,’ a prior art parallelcommunications library, a module of computer program instructions fordata communications on parallel computers. Examples of prior-artparallel communications libraries that may be improved for use withsystems according to embodiments of the present invention include MPIand the ‘Parallel Virtual Machine’ (‘PVM’) library. PVM was developed bythe University of Tennessee, The Oak Ridge National Laboratory, andEmory University. MPI is promulgated by the MPI Forum, an open groupwith representatives from many organizations that define and maintainthe MPI standard. MPI at the time of this writing is a de facto standardfor communication among compute nodes running a parallel program on adistributed memory parallel computer. This specification sometimes usesMPI terminology for ease of explanation, although the use of MPI as suchis not a requirement or limitation of the present invention.

Some collective operations have a single originating or receivingprocess running on a particular compute node in an operational group.For example, in a ‘broadcast’ collective operation, the process on thecompute node that distributes the data to all the other compute nodes isan originating process. In a ‘gather’ operation, for example, theprocess on the compute node that received all the data from the othercompute nodes is a receiving process. The compute node on which such anoriginating or receiving process runs is referred to as a logical root.

Most collective operations are variations or combinations of four basicoperations: broadcast, gather, scatter, and reduce. The interfaces forthese collective operations are defined in the MPI standards promulgatedby the MPI Forum. Algorithms for executing collective operations,however, are not defined in the MPI standards. In a broadcast operation,all processes specify the same root process, whose buffer contents willbe sent. Processes other than the root specify receive buffers. Afterthe operation, all buffers contain the message from the root process.

In a scatter operation, the logical root divides data on the root intosegments and distributes a different segment to each compute node in theoperational group. In scatter operation, all processes typically specifythe same receive count. The send arguments are only significant to theroot process, whose buffer actually contains sendcount * N elements of agiven data type, where N is the number of processes in the given groupof compute nodes. The send buffer is divided and dispersed to allprocesses (including the process on the logical root). Each compute nodeis assigned a sequential identifier termed a ‘rank.’ After theoperation, the root has sent sendcount data elements to each process inincreasing rank order. Rank 0 receives the first sendcount data elementsfrom the send buffer. Rank 1 receives the second sendcount data elementsfrom the send buffer, and so on.

A gather operation is a many-to-one collective operation that is acomplete reverse of the description of the scatter operation. That is, agather is a many-to-one collective operation in which elements of adatatype are gathered from the ranked compute nodes into a receivebuffer in a root node.

A reduce operation is also a many-to-one collective operation thatincludes an arithmetic or logical function performed on two dataelements. All processes specify the same ‘count’ and the same arithmeticor logical function. After the reduction, all processes have sent countdata elements from computer node send buffers to the root process. In areduction operation, data elements from corresponding send bufferlocations are combined pair-wise by arithmetic or logical operations toyield a single corresponding element in the root process's receivebuffer. Application specific reduction operations can be defined atruntime. Parallel communications libraries may support predefinedoperations. MPI, for example, provides the following predefinedreduction operations:

MPI_MAX maximum MPI_MIN minimum MPI_SUM sum MPI_PROD product MPI_LANDlogical and MPI_BAND bitwise and MPI_LOR logical or MPI_BOR bitwise orMPI_LXOR logical exclusive or MPI_BXOR bitwise exclusive or

In addition to compute nodes, the parallel computer (100) includesinput/output (‘I/O’) nodes (110, 114) coupled to compute nodes (102)through the global combining network (106). The compute nodes in theparallel computer (100) are partitioned into processing sets such thateach compute node in a processing set is connected for datacommunications to the same I/O node. Each processing set, therefore, iscomposed of one I/O node and a subset of compute nodes (102). The ratiobetween the number of compute nodes to the number of I/O nodes in theentire system typically depends on the hardware configuration for theparallel computer. For example, in some configurations, each processingset may be composed of eight compute nodes and one I/O node. In someother configurations, each processing set may be composed of sixty-fourcompute nodes and one I/O node. Such example are for explanation only,however, and not for limitation. Each I/O nodes provide I/O servicesbetween compute nodes (102) of its processing set and a set of I/Odevices. In the example of FIG. 1, the I/O nodes (110, 114) areconnected for data communications I/O devices (118, 120, 122) throughlocal area network (‘LAN’) (130) implemented using high-speed Ethernet.

The parallel computer (100) of FIG. 1 also includes a service node (116)coupled to the compute nodes through one of the networks (104). Servicenode (116) provides services common to pluralities of compute nodes,administering the configuration of compute nodes, loading programs intothe compute nodes, starting program execution on the compute nodes,retrieving results of program operations on the computer nodes, and soon. Service node (116) runs a service application (124) and communicateswith users (128) through a service application interface (126) that runson computer terminal (122).

In the example of FIG. 1, the plurality of compute nodes (102) areimplemented in a parallel computer (100) and are connected togetherusing a plurality of data communications networks (104, 106, 108). Thepoint to point network (108) is optimized for point to point operations.The global combining network (106) is optimized for collectiveoperations. Although tracking data processing in an application carriedout on a distributed computing system according to embodiments of thepresent invention is described above in terms of an architecture for aparallel computer, readers will note that such an embodiment is forexplanation only and not for limitation. In fact, tracking dataprocessing in an application carried out on a distributed computingsystem according to embodiments of the present invention may beimplemented using a variety of distributed computer system architecturescomposed of a plurality of nodes network-connected together, includingfor example architectures for a cluster of nodes, a grid computingsystem, and so on.

The arrangement of nodes, networks, and I/O devices making up theexemplary system illustrated in FIG. 1 are for explanation only, not forlimitation of the present invention. Data processing systems capable oftracking data processing in an application carried out on a distributedcomputing system according to embodiments of the present invention mayinclude additional nodes, networks, devices, and architectures, notshown in FIG. 1, as will occur to those of skill in the art. Althoughthe parallel computer (100) in the example of FIG. 1 includes sixteencompute nodes (102), readers will note that parallel computers capableof tracking data processing in an application carried out on adistributed computing system according to embodiments of the presentinvention may include any number of compute nodes. In addition toEthernet and JTAG, networks in such data processing systems may supportmany data communications protocols including for example TCP(Transmission Control Protocol), IP (Internet Protocol), and others aswill occur to those of skill in the art. Various embodiments of thepresent invention may be implemented on a variety of hardware platformsin addition to those illustrated in FIG. 1.

Tracking data processing in an application carried out on a distributedcomputing system according to embodiments of the present invention maybe generally implemented on a parallel computer that includes aplurality of compute nodes, among other types of exemplary systems. Infact, such computers may include thousands of such compute nodes. Eachcompute node is in turn itself a kind of computer composed of one ormore computer processors, its own computer memory, and its owninput/output adapters. For further explanation, therefore, FIG. 2 setsforth a block diagram of an exemplary compute node (152) useful in aparallel computer capable of tracking data processing in an applicationcarried out on a distributed computing system (210) according toembodiments of the present invention. The compute node (152) of FIG. 2includes one or more computer processors (164) as well as random accessmemory (‘RAM’) (156). The processors (164) are connected to RAM (156)through a high-speed memory bus (154) and through a bus adapter (194)and an extension bus (168) to other components of the compute node(152).

Stored in RAM (156) of FIG. 2 are one or more pluggable processingcomponents (210) used to carry out an application. As mentioned above, apluggable processing component is a set of computer program instructionsthat when executed performs a particular task that is a logical,discrete, reusable building block for more complex software systems. Thepluggable processing components (210) of FIG. 2 include pluggableprocessing provider components and pluggable processing consumercomponents. In the example of FIG. 2, both the pluggable processingprovider components and the pluggable processing consumer componentsoperate generally for tracking data processing in an application carriedout on a distributed computing system according to embodiments of thepresent invention. The pluggable processing provider components operategenerally for tracking data processing in an application carried out ona distributed computing system according to embodiments of the presentinvention by: identifying data satisfying predetermined processingcriteria, the predetermined processing criteria specifying that the datais relevant to processing provided by the pluggable processing consumercomponent; and passing the data to the next pluggable processingcomponent in the application for processing, including maintainingaccess to the data. The pluggable processing consumer components operategenerally for tracking data processing in an application carried out ona distributed computing system according to embodiments of the presentinvention by: receiving the data during execution of the application;and sending a receipt indicating that the pluggable processing consumercomponent received the data.

The pluggable processing provider components may also operate generallyfor tracking data processing in an application carried out on adistributed computing system according to embodiments of the presentinvention by: receiving, from the pluggable processing consumercomponent, the receipt indicating that the pluggable processing consumercomponent received the data; and administering the data in response toreceiving the receipt. Because a pluggable processing provider componentmay not always receive the receipt from the consumer component, thepluggable processing provider components may operate generally fortracking data processing in an application carried out on a distributedcomputing system according to embodiments of the present invention by:determining that the pluggable processing provider component did notreceive the receipt within a predefined time period; and performing oneor more corrective actions in response to not receiving the receiptwithin a predefined time period.

Also installed in RAM (156) of FIG. 2 is a system administrativecomponent (702). The system administrative component (702) of FIG. 2 isa set of computer program instructions for managing the plurality ofpluggable processing components carrying out the application (200). Insome embodiments, the pluggable processing consumer components may nothave enough information about the provider component to send a receiptdirectly to the provider component. In such embodiments, the systemadministrative component (702) may operate generally for tracking dataprocessing in the application (200) carried out on a distributedcomputing system according to embodiments of the present invention by:receiving, from the pluggable processing consumer component, the receiptindicating that the pluggable processing consumer component received thedata; and sending, to the pluggable processing provider component, thereceipt indicating that the pluggable processing consumer componentreceived the data. The pluggable processing provider component may inturn operate for tracking data processing in the application (200)carried out on a distributed computing system according to embodimentsof the present invention by: receiving, from the system administrativecomponent, the receipt indicating that the pluggable processing consumercomponent received the data; and administering the data in response toreceiving the receipt.

Also stored RAM (156) is a messaging module (161), a library of computerprogram instructions that carry out parallel communications amongcompute nodes, including point to point operations as well as collectiveoperations. The pluggable processing components (210) effect datacommunications among one another and with other applications running onother compute nodes by calling software routines in the messagingmodules (161). A library of parallel communications routines may bedeveloped from scratch for use in systems according to embodiments ofthe present invention, using a traditional programming language such asthe C programming language, and using traditional programming methods towrite parallel communications routines. Alternatively, existing priorart libraries may be used such as, for example, the ‘Message PassingInterface’ (‘MPI’) library, the ‘Parallel Virtual Machine’ (‘PVM’)library, and the Aggregate Remote Memory Copy Interface (‘ARMCI’)library.

Also stored in RAM (156) is an operating system (162), a module ofcomputer program instructions and routines for an application program'saccess to other resources of the compute node. It is typical for anapplication program and parallel communications library in a computenode of a parallel computer to run a single thread of execution with nouser login and no security issues because the thread is entitled tocomplete access to all resources of the node. The quantity andcomplexity of tasks to be performed by an operating system on a computenode in a parallel computer therefore are smaller and less complex thanthose of an operating system on a serial computer with many threadsrunning simultaneously. In addition, there is no video I/O on thecompute node (152) of FIG. 2, another factor that decreases the demandson the operating system. The operating system may therefore be quitelightweight by comparison with operating systems of general purposecomputers, a pared down version as it were, or an operating systemdeveloped specifically for operations on a particular parallel computer.Operating systems that may usefully be improved, simplified, for use ina compute node include UNIX™, Linux™, Microsoft Vista™, AIX™, IBM'si5/OS™, and others as will occur to those of skill in the art.

The exemplary compute node (152) of FIG. 2 includes severalcommunications adapters (172, 176, 180, 188) for implementing datacommunications with other nodes of a parallel computer. Such datacommunications may be carried out serially through RS-232 connections,through external buses such as USB, through data communications networkssuch as IP networks, and in other ways as will occur to those of skillin the art. Communications adapters implement the hardware level of datacommunications through which one computer sends data communications toanother computer, directly or through a network. Examples ofcommunications adapters useful in systems for tracking data processingin an application carried out on a distributed computing systemaccording to embodiments of the present invention include modems forwired communications, Ethernet (IEEE 802.3) adapters for wired networkcommunications, and 802.11b adapters for wireless networkcommunications.

The data communications adapters in the example of FIG. 2 include aGigabit Ethernet adapter (172) that couples example compute node (152)for data communications to a Gigabit Ethernet (174). Gigabit Ethernet isa network transmission standard, defined in the IEEE 802.3 standard,that provides a data rate of 1 billion bits per second (one gigabit).Gigabit Ethernet is a variant of Ethernet that operates over multimodefiber optic cable, single mode fiber optic cable, or unshielded twistedpair.

The data communications adapters in the example of FIG. 2 includes aJTAG Slave circuit (176) that couples example compute node (152) fordata communications to a JTAG Master circuit (178). JTAG is the usualname used for the IEEE 1149.1 standard entitled Standard Test AccessPort and Boundary-Scan Architecture for test access ports used fortesting printed circuit boards using boundary scan. JTAG is so widelyadapted that, at this time, boundary scan is more or less synonymouswith JTAG. JTAG is used not only for printed circuit boards, but alsofor conducting boundary scans of integrated circuits, and is also usefulas a mechanism for debugging embedded systems, providing a convenient“back door” into the system. The example compute node of FIG. 2 may beall three of these: It typically includes one or more integratedcircuits installed on a printed circuit board and may be implemented asan embedded system having its own processor, its own memory, and its ownI/O capability. JTAG boundary scans through JTAG Slave (176) mayefficiently configure processor registers and memory in compute node(152) for use in tracking data processing in an application carried outon a distributed computing system according to embodiments of thepresent invention.

The data communications adapters in the example of FIG. 2 includes aPoint To Point Adapter (180) that couples example compute node (152) fordata communications to a network (108) that is optimal for point topoint message passing operations such as, for example, a networkconfigured as a three-dimensional torus or mesh. Point To Point Adapter(180) provides data communications in six directions on threecommunications axes, x, y, and z, through six bidirectional links: +x(181), −x (182), +y (183), −y (184), +z (185), and −z (186).

The data communications adapters in the example of FIG. 2 includes aGlobal Combining Network Adapter (188) that couples example compute node(152) for data communications to a network (106) that is optimal forcollective message passing operations on a global combining networkconfigured, for example, as a binary tree. The Global Combining NetworkAdapter (188) provides data communications through three bidirectionallinks: two to children nodes (190) and one to a parent node (192).

Example compute node (152) includes two arithmetic logic units (‘ALUs’).ALU (166) is a component of processor (164), and a separate ALU (170) isdedicated to the exclusive use of Global Combining Network Adapter (188)for use in performing the arithmetic and logical functions of reductionoperations. Computer program instructions of a reduction routine inparallel communications library (160) may latch an instruction for anarithmetic or logical function into instruction register (169). When thearithmetic or logical function of a reduction operation is a ‘sum’ or a‘logical or,’ for example, Global Combining Network Adapter (188) mayexecute the arithmetic or logical operation by use of ALU (166) inprocessor (164) or, typically much faster, by use dedicated ALU (170).

The example compute node (152) of FIG. 2 includes a direct memory access(‘DMA’) controller (195), which is computer hardware for direct memoryaccess and a DMA engine (195), which is computer software for directmemory access. Direct memory access includes reading and writing tomemory of compute nodes with reduced operational burden on the centralprocessing units (164). A DMA transfer essentially copies a block ofmemory from one compute node to another. While the CPU may initiates theDMA transfer, the CPU does not execute it. In the example of FIG. 2, theDMA engine (195) and the DMA controller (195) support the messagingmodule (161).

For further explanation, FIG. 3A illustrates an exemplary Point To PointAdapter (180) useful in distributed computing systems capable oftracking data processing in an application carried out on thedistributed computing system according to embodiments of the presentinvention. Point To Point Adapter (180) is designed for use in a datacommunications network optimized for point to point operations, anetwork that organizes compute nodes in a three-dimensional torus ormesh. Point To Point Adapter (180) in the example of FIG. 3A providesdata communication along an x-axis through four unidirectional datacommunications links, to and from the next node in the −x direction(182) and to and from the next node in the +x direction (181). Point ToPoint Adapter (180) also provides data communication along a y-axisthrough four unidirectional data communications links, to and from thenext node in the −y direction (184) and to and from the next node in the+y direction (183). Point To Point Adapter (180) in FIG. 3A alsoprovides data communication along a z-axis through four unidirectionaldata communications links, to and from the next node in the −z direction(186) and to and from the next node in the +z direction (185).

For further explanation, FIG. 3B illustrates an exemplary GlobalCombining Network Adapter (188) useful in distributed computing systemscapable of tracking data processing in an application carried out on thedistributed computing system according to embodiments of the presentinvention. Global Combining Network Adapter (188) is designed for use ina network optimized for collective operations, a network that organizescompute nodes of a parallel computer in a binary tree. Global CombiningNetwork Adapter (188) in the example of FIG. 3B provides datacommunication to and from two children nodes through four unidirectionaldata communications links (190). Global Combining Network Adapter (188)also provides data communication to and from a parent node through twounidirectional data communications links (192).

For further explanation, FIG. 4 sets forth a line drawing illustratingan exemplary data communications network (108) optimized for point topoint operations useful in distributed computing systems capable oftracking data processing in an application carried out on a distributedcomputing system in accordance with embodiments of the presentinvention. In the example of FIG. 4, dots represent compute nodes (102)of a parallel computer, and the dotted lines between the dots representdata communications links (103) between compute nodes. The datacommunications links are implemented with point to point datacommunications adapters similar to the one illustrated for example inFIG. 3A, with data communications links on three axes, x, y, and z, andto and fro in six directions +x (181), −x (182), +y (183), −y (184), +z(185), and −z (186). The links and compute nodes are organized by thisdata communications network optimized for point to point operations intoa three dimensional mesh (105). The mesh (105) has wrap-around links oneach axis that connect the outermost compute nodes in the mesh (105) onopposite sides of the mesh (105). These wrap-around links form part of atorus (107). Each compute node in the torus has a location in the torusthat is uniquely specified by a set of x, y, z coordinates. Readers willnote that the wrap-around links in the y and z directions have beenomitted for clarity, but are configured in a similar manner to thewrap-around link illustrated in the x direction. For clarity ofexplanation, the data communications network of FIG. 4 is illustratedwith only 27 compute nodes, but readers will recognize that a datacommunications network optimized for point to point operations for usein tracking data processing in an application carried out on adistributed computing system in accordance with embodiments of thepresent invention may contain only a few compute nodes or may containthousands of compute nodes.

For further explanation, FIG. 5 sets forth a line drawing illustratingan exemplary data communications network (106) optimized for collectiveoperations useful in systems capable of tracking data processing in anapplication carried out on a distributed computing system in accordancewith embodiments of the present invention. The example datacommunications network of FIG. 5 includes data communications linksconnected to the compute nodes so as to organize the compute nodes as atree. In the example of FIG. 5, dots represent compute nodes (102) of aparallel computer, and the dotted lines (103) between the dots representdata communications links between compute nodes. The data communicationslinks are implemented with global combining network adapters similar tothe one illustrated for example in FIG. 3B, with each node typicallyproviding data communications to and from two children nodes and datacommunications to and from a parent node, with some exceptions. Nodes ina binary tree (106) may be characterized as a physical root node (202),branch nodes (204), and leaf nodes (206). The root node (202) has twochildren but no parent. The leaf nodes (206) each has a parent, but leafnodes have no children. The branch nodes (204) each has both a parentand two children. The links and compute nodes are thereby organized bythis data communications network optimized for collective operationsinto a binary tree (106). For clarity of explanation, the datacommunications network of FIG. 5 is illustrated with only 31 computenodes, but readers will recognize that a data communications networkoptimized for collective operations for use in systems for tracking dataprocessing in an application carried out on a distributed computingsystem in accordance with embodiments of the present invention maycontain only a few compute nodes or may contain thousands of computenodes.

In the example of FIG. 5, each node in the tree is assigned a unitidentifier referred to as a ‘rank’ (250). A node's rank uniquelyidentifies the node's location in the tree network for use in both pointto point and collective operations in the tree network. The ranks inthis example are assigned as integers beginning with 0 assigned to theroot node (202), 1 assigned to the first node in the second layer of thetree, 2 assigned to the second node in the second layer of the tree, 3assigned to the first node in the third layer of the tree, 4 assigned tothe second node in the third layer of the tree, and so on. For ease ofillustration, only the ranks of the first three layers of the tree areshown here, but all compute nodes in the tree network are assigned aunique rank.

For further explanation, FIG. 6 sets forth a flow chart illustrating anexemplary method for tracking data processing in an application carriedout on a distributed computing system according to embodiments of thepresent invention. The distributed computing system described withreference to FIG. 6 includes a plurality of computing nodes connectedfor data communications through a data communications network. Theapplication carried out by a plurality of pluggable processingcomponents (210) installed on the plurality of computing nodes. Thepluggable processing components (210) include a pluggable processingprovider component (600) and a pluggable processing consumer component(602).

The method of FIG. 6 includes identifying (606), by the pluggableprocessing provider component (600), data satisfying predeterminedprocessing criteria (604). The predetermined processing criteria (604)of FIG. 6 represents a data structure that specifies data that isrelevant to processing provided by the pluggable processing consumercomponent (602). That is, the pluggable processing provider component(600) uses the predetermined processing criteria (604) to determinewhether data produced by the provider component (600) is data that isconsumed by the consumer component (602). The predetermined processingcriteria (604) of FIG. 6 may specify data that is relevant to processingprovided by the pluggable processing consumer component (602) byassociating a data type identifier with an identifier for the pluggableprocessing consumer component (602). The pluggable processing providercomponent (600) may identify (606) data satisfying predeterminedprocessing criteria (604) according to the method of FIG. 6 by comparingthe data type for the data and determining whether that particular datatype is associated with the identifier for the pluggable processingconsumer component (602) in the predetermined processing criteria (604).If that particular data type is associated with the identifier for thepluggable processing consumer component (602) in the predeterminedprocessing criteria (604), then the data satisfies predeterminedprocessing criteria (604). The data satisfies predetermined processingcriteria (604), however, if that particular data type is not associatedwith the identifier for the pluggable processing consumer component(602) in the predetermined processing criteria (604). Readers will notethat the predetermined processing criteria (604) and the manner ofidentifying (606), by the pluggable processing provider component (600),data satisfying predetermined processing criteria (604) described aboveis for explanation only and not for limitation.

The method of FIG. 6 also includes passing (610), by the pluggableprocessing provider component (600), the data (608) to the nextpluggable processing component in the application for processing. Thenext pluggable processing component may be the consumer component (602)or an interim component in the data flow between the provider component(600) and the consumer component (602), which eventually receives thedata (608). The pluggable processing provider component (600) may pass(610) the data (608) to the next pluggable processing component in theapplication for processing according to the method of FIG. 6 byproviding the data (608) to a messaging module, which in turnencapsulates the data (608) into packets and transmits the packets tothe next pluggable processing component.

In the method of FIG. 6, passing (610), by the pluggable processingprovider component (600), the data (608) to the next pluggableprocessing component in the application for processing includesmaintaining (612) access to the data (608). The pluggable processingprovider component (600) typically maintains access to the data in theevent that the pluggable processing consumer component (600) does noteventually receive the data (608). Maintaining (612) access to the data(608) according to the method of FIG. 6 may be carried out by storingthe data (608) in computer memory of the pluggable processing providercomponent (600) or storing information used by the pluggable processingprovider component (600) to recreate the data (608).

The method of FIG. 6 includes receiving (616), by the pluggableprocessing consumer component (602), the data (608) during execution ofthe application. The pluggable processing consumer component (602) mayreceive (616) the data (608) during execution of the applicationaccording to the method of FIG. 6 by receiving the data (608) as aparameter of a callback function provided to messaging module, which inturn receives multiple network packets and unencapsulates the data (608)from the network packets.

The method of FIG. 6 also includes sending (620), by the pluggableprocessing consumer component (602), a receipt (624) indicating that thepluggable processing consumer component (602) received the data (608).The pluggable processing consumer component (602) sends (620) a receipt(624) according to the method of FIG. 6 by identifying when thepluggable processing consumer component (602) receives all of the data(608) and transmitting a receipt (624) to the pluggable processingprovider indicating that the pluggable processing consumer component(602) receives all of the data (608). The pluggable processing consumercomponent (602) may identify when the pluggable processing consumercomponent (602) receives all of the data (608) by detecting when amessaging module stores an identifier for the data (608) in a networkinput buffer for the consumer component (602). The messaging module mayreceive the data (608) by unencapsulating the data (608) from networkpackets received from the pluggable processing provider component (600).The pluggable processing consumer component (602) may transmitting thereceipt (624) by passing the receipt (624) to a messaging module, whichin turn encapsulates the receipt (624) into network packets andtransfers the packets to the provider component (600).

The method of FIG. 6 includes receiving (622), by the pluggableprocessing provider component (600) from the pluggable processingconsumer component (602), the receipt (624) indicating that thepluggable processing consumer component (602) received the data (608).The pluggable processing provider component (600) may receive (622) thereceipt (624) from the pluggable processing consumer component (602)according to the method of FIG. 6 by detecting when a messaging modulestores an identifier for the receipt (624) in a network input buffer ofthe provider component (600). The messaging module may receive thereceipt (624) by unencapsulating the receipt (624) from network packetsreceived from the pluggable processing consumer component (602).

The method of FIG. 6 also includes administering (626), by the pluggableprocessing provider component (602), the data (608) in response toreceiving the receipt (624). The pluggable processing provider component(600) may administer (626) the data (608) in response to receiving thereceipt (624) according to the method of FIG. 6 by discarding the data(608) or the information used to create the data (608). The providercomponent (600) may discard the data (608) or the information used tocreate the data (608) because the receipt (624) indicates that theprovider component (600) does not need to resend the data to theconsumer component (602). Unless there are other uses for the data (608)or the information used to create the data (608), the provider component(600) has no need to maintain the data (608) or the information used tocreate the data (608).

The explanation above with reference to FIG. 6 describes a pluggableprocessing consumer component that communicates directly with apluggable processing provider component by sending the providercomponent a receipt for data received by the consumer component. In someother embodiments, the pluggable processing consumer component may relaythe receipt to the provider component via a third-party component,namely a system administrative component. For further explanation,therefore, FIG. 7 sets forth a flow chart illustrating a furtherexemplary method for tracking data processing in an application carriedout on a distributed computing system according to embodiments of thepresent invention. The distributed computing system described withreference to FIG. 7 includes a plurality of computing nodes connectedfor data communications through a data communications network. Theapplication carried out by a plurality of pluggable processingcomponents (210) installed on the plurality of computing nodes. Thepluggable processing components (210) include a pluggable processingprovider component (600) and a pluggable processing consumer component(602).

The method of FIG. 7 is similar to the method of FIG. 6. That is, themethod of FIG. 7 includes: identifying (606), by the pluggableprocessing provider component (600), data satisfying predeterminedprocessing criteria (604), the predetermined processing criteria (604)specifying that the data is relevant to processing provided by thepluggable processing consumer component (602); passing (610), by thepluggable processing provider component (600), the data (608) to thenext pluggable processing component in the application for processing,including maintaining (612) access to the data (608); receiving (616),by the pluggable processing consumer component (602), the data (608)during execution of the application; and sending (620), by the pluggableprocessing consumer component (602), a receipt (706) indicating that thepluggable processing consumer component (602) received the data (608).

The method of FIG. 7 also includes receiving (704), by a systemadministrative component (702) from the pluggable processing consumercomponent (602), the receipt (706) indicating that the pluggableprocessing consumer component (602) received the data (608). The systemadministrative component (702) may receive (704) the receipt (706) fromthe pluggable processing consumer component (602) according to themethod of FIG. 7 by detecting when a messaging module stores anidentifier for the receipt (706) in a network input buffer of theadministrative component (702). The messaging module may receive thereceipt (706) by unencapsulating the receipt (706) from network packetsreceived from the pluggable processing consumer component (602).

The method of FIG. 7 includes sending (708), by the systemadministrative component (702) to the pluggable processing providercomponent (600), the receipt (706) indicating that the pluggableprocessing consumer component (602) received the data (608). The systemadministrative component (702) may send (708) the receipt (706) to thepluggable processing provider component (600) indicating that thepluggable processing consumer component (602) received the data (608)according to the method of FIG. 7 by passing the receipt (706) to amessaging module, which in turn encapsulates the receipt (706) intonetwork packets and transmits the packets to the provider component(600).

The method of FIG. 7 also includes receiving (710), by the pluggableprocessing provider component (600) from the system administrativecomponent (702), the receipt (706) indicating that the pluggableprocessing consumer component (602) received the data (608). Thepluggable processing provider component (600) may receive (710) thereceipt (706) from the system administrative component (702) accordingto the method of FIG. 7 by detecting when a messaging module stores anidentifier for the receipt (706) in a network input buffer of theprovider component (600). The messaging module may receive the receipt(706) by unencapsulating the receipt (706) from network packets receivedfrom the system administrative component (702).

The method of FIG. 7 includes administering (712), by the pluggableprocessing provider component (600), the data (608) in response toreceiving the receipt (706). The pluggable processing provider component(600) may administer (712) the data (608) in response to receiving thereceipt (706) according to the method of FIG. 7 by discarding the data(608) or the information used to create the data (608). The providercomponent (600) may discard the data (608) or the information used tocreate the data (608) because the receipt (706) indicates that theprovider component (600) does not need to resend the data to theconsumer component (602). Unless there are other uses for the data (608)or the information used to create the data (608), the provider component(600) has no need to maintain the data (608) or the information used tocreate the data (608).

The explanation above with reference to FIGS. 6 and 7 describesembodiments in which the pluggable processing consumer componentreceives the data and sends a receipt to the pluggable processingprovider component, which in turn discards the data. In some otherembodiments, the pluggable processing provider component may not receivethe receipt from the pluggable processing consumer component because theconsumer component never receives the data. For further explanation,therefore, FIG. 8 sets forth a flow chart illustrating a furtherexemplary method for tracking data processing in an application carriedout on a distributed computing system according to embodiments of thepresent invention. The distributed computing system described withreference to FIG. 8 includes a plurality of computing nodes connectedfor data communications through a data communications network. Theapplication carried out by a plurality of pluggable processingcomponents (210) installed on the plurality of computing nodes. Thepluggable processing components (210) include a pluggable processingprovider component (600) and a pluggable processing consumer component(602).

The method of FIG. 8 is similar to the method of FIG. 6. That is, themethod of FIG. 8 includes: identifying (606), by the pluggableprocessing provider component (600), data satisfying predeterminedprocessing criteria (604), the predetermined processing criteria (604)specifying that the data is relevant to processing provided by thepluggable processing consumer component (602); passing (610), by thepluggable processing provider component (600), the data (608) to thenext pluggable processing component in the application for processing,including maintaining (612) access to the data (608); receiving (616),by the pluggable processing consumer component (602), the data (608)during execution of the application; and sending (620), by the pluggableprocessing consumer component (602), a receipt (624) indicating that thepluggable processing consumer component (602) received the data (608).

The method of FIG. 8 includes determining (802), by the pluggableprocessing provider component (600), that the pluggable processingprovider component (600) did not receive the receipt (624) within apredefined time period (800). The pluggable processing providercomponent (600) may determine (802) that the pluggable processingprovider component (600) did not receive the receipt (624) within apredefined time period (800) according to the method of FIG. 8 bycomparing the predefined time period (800) with the elapsed time periodbetween when the data (608) was passed to the consumer component (602)and the current time. When the elapsed time period between when the data(608) was passed to the consumer component (602) and the current timeexceeds the predefined time period (800), then the pluggable processingprovider component (600) did not receive the receipt (624) within thepredefined time period (800). The pluggable processing providercomponent (600) may not have received the receipt (624) within thepredefined time period (800) because the consumer component (602) neverreceived the data (608), the consumer component (602) failed to generatethe receipt (624), the receipt (624) was lost during transmission, andso on.

The method of FIG. 8 also includes performing (804), by the pluggableprocessing provider component (600), one or more corrective actions inresponse to not receiving the receipt within a predefined time period(800). The pluggable processing provider component (600) may perform(804) a corrective action according to the method of FIG. 8 by queryingthe consumer component (602) to discover whether the consumer component(602) did not receive the data (608), why the receipt (624) was notsent, and so on. The query information may be recorded in an error logfor later review by a system administrator. In addition, the pluggableprocessing provider component (600) may perform (804) a correctiveaction according to the method of FIG. 8 by resending the data (608) tothe pluggable processing consumer component (602).

Exemplary embodiments of the present invention are described largely inthe context of a fully functional computer system for tracking dataprocessing in an application carried out on a distributed computingsystem. Readers of skill in the art will recognize, however, that thepresent invention also may be embodied in a computer program productdisposed on computer readable media for use with any suitable dataprocessing system. Such computer readable media may be transmissionmedia or recordable media for machine-readable information, includingmagnetic media, optical media, or other suitable media. Examples ofrecordable media include magnetic disks in hard drives or diskettes,compact disks for optical drives, magnetic tape, and others as willoccur to those of skill in the art. Examples of transmission mediainclude telephone networks for voice communications and digital datacommunications networks such as, for example, Ethernets™ and networksthat communicate with the Internet Protocol and the World Wide Web aswell as wireless transmission media such as, for example, networksimplemented according to the IEEE 802.11 family of specifications.Persons skilled in the art will immediately recognize that any computersystem having suitable programming means will be capable of executingthe steps of the method of the invention as embodied in a programproduct. Persons skilled in the art will recognize immediately that,although some of the exemplary embodiments described in thisspecification are oriented to software installed and executing oncomputer hardware, nevertheless, alternative embodiments implemented asfirmware or as hardware are well within the scope of the presentinvention.

It will be understood from the foregoing description that modificationsand changes may be made in various embodiments of the present inventionwithout departing from its true spirit. The descriptions in thisspecification are for purposes of illustration only and are not to beconstrued in a limiting sense. The scope of the present invention islimited only by the language of the following claims.

1. A method of tracking data processing in an application carried out ona distributed computing system, the distributed computing systemcomprising a plurality of computing nodes connected for datacommunications through a data communications network, the applicationcarried out by a plurality of pluggable processing components installedon the plurality of computing nodes, the pluggable processing componentsincluding a pluggable processing provider component and a pluggableprocessing consumer component, the method comprising: identifying, bythe pluggable processing provider component, data satisfyingpredetermined processing criteria, the predetermined processing criteriaspecifying that the data is relevant to processing provided by thepluggable processing consumer component; passing, by the pluggableprocessing provider component, the data to the next pluggable processingcomponent in the application for processing, including maintainingaccess to the data; receiving, by the pluggable processing consumercomponent, the data during execution of the application; and sending, bythe pluggable processing consumer component, a receipt indicating thatthe pluggable processing consumer component received the data.
 2. Themethod of claim 1 further comprising: receiving, by the pluggableprocessing provider component from the pluggable processing consumercomponent, the receipt indicating that the pluggable processing consumercomponent received the data; and administering, by the pluggableprocessing provider component, the data in response to receiving thereceipt.
 3. The method of claim 1 further comprising: receiving, by asystem administrative component from the pluggable processing consumercomponent, the receipt indicating that the pluggable processing consumercomponent received the data; sending, by the system administrativecomponent to the pluggable processing provider component, the receiptindicating that the pluggable processing consumer component received thedata; receiving, by the pluggable processing provider component from thesystem administrative component, the receipt indicating that thepluggable processing consumer component received the data; andadministering, by the pluggable processing provider component, the datain response to receiving the receipt.
 4. The method of claim 1 furthercomprising: determining, by the pluggable processing provider component,that the pluggable processing provider component did not receive thereceipt within a predefined time period; and performing, by thepluggable processing provider component, one or more corrective actionsin response to not receiving the receipt within a predefined timeperiod.
 5. The method of claim 1 wherein maintaining access to the datafurther comprises storing the data in computer memory of the pluggableprocessing provider component.
 6. The method of claim 1 whereinmaintaining access to the data further comprises storing informationused by the pluggable processing provider component to recreate thedata.
 7. A distributed computing system capable of tracking dataprocessing in an application carried out on the distributed computingsystem, the distributed computing system comprising a plurality ofcomputing nodes connected for data communications through a datacommunications network, the application carried out by a plurality ofpluggable processing components installed on the plurality of computingnodes, the pluggable processing components including a pluggableprocessing provider component and a pluggable processing consumercomponent, the distributed computing system comprising one or morecomputer processors and computer memory operatively coupled to thecomputer processors, the computer memory for the distributed computingsystem having disposed within it computer program instructions capableof: identifying, by the pluggable processing provider component, datasatisfying predetermined processing criteria, the predeterminedprocessing criteria specifying that the data is relevant to processingprovided by the pluggable processing consumer component; passing, by thepluggable processing provider component, the data to the next pluggableprocessing component in the application for processing, includingmaintaining access to the data; receiving, by the pluggable processingconsumer component, the data during execution of the application; andsending, by the pluggable processing consumer component, a receiptindicating that the pluggable processing consumer component received thedata.
 8. The distributed computing system of claim 7 wherein thecomputer memory for the distributed computing system has disposed withinit computer program instructions capable of: receiving, by the pluggableprocessing provider component from the pluggable processing consumercomponent, the receipt indicating that the pluggable processing consumercomponent received the data; and administering, by the pluggableprocessing provider component, the data in response to receiving thereceipt.
 9. The distributed computing system of claim 7 wherein thecomputer memory for the distributed computing system has disposed withinit computer program instructions capable of: receiving, by a systemadministrative component from the pluggable processing consumercomponent, the receipt indicating that the pluggable processing consumercomponent received the data; sending, by the system administrativecomponent to the pluggable processing provider component, the receiptindicating that the pluggable processing consumer component received thedata; receiving, by the pluggable processing provider component from thesystem administrative component, the receipt indicating that thepluggable processing consumer component received the data; andadministering, by the pluggable processing provider component, the datain response to receiving the receipt.
 10. The distributed computingsystem of claim 7 wherein the computer memory for the distributedcomputing system has disposed within it computer program instructionscapable of: determining, by the pluggable processing provider component,that the pluggable processing provider component did not receive thereceipt within a predefined time period; and performing, by thepluggable processing provider component, one or more corrective actionsin response to not receiving the receipt within a predefined timeperiod.
 11. The distributed computing system of claim 7 whereinmaintaining access to the data further comprises storing the data incomputer memory of the pluggable processing provider component.
 12. Thedistributed computing system of claim 7 wherein maintaining access tothe data further comprises storing information used by the pluggableprocessing provider component to recreate the data.
 13. A computerprogram product for tracking data processing in an application carriedout on a distributed computing system, the distributed computing systemcomprising a plurality of computing nodes connected for datacommunications through a data communications network, the applicationcarried out by a plurality of pluggable processing components installedon the plurality of computing nodes, the pluggable processing componentsincluding a pluggable processing provider component and a pluggableprocessing consumer component, the computer program product disposedupon a computer readable medium, the computer program product comprisingcomputer program instructions capable of: identifying, by the pluggableprocessing provider component, data satisfying predetermined processingcriteria, the predetermined processing criteria specifying that the datais relevant to processing provided by the pluggable processing consumercomponent; passing, by the pluggable processing provider component, thedata to the next pluggable processing component in the application forprocessing, including maintaining access to the data; receiving, by thepluggable processing consumer component, the data during execution ofthe application; and sending, by the pluggable processing consumercomponent, a receipt indicating that the pluggable processing consumercomponent received the data.
 14. The computer program product of claim13 further comprising computer program instructions capable of:receiving, by the pluggable processing provider component from thepluggable processing consumer component, the receipt indicating that thepluggable processing consumer component received the data; andadministering, by the pluggable processing provider component, the datain response to receiving the receipt.
 15. The computer program productof claim 13 further comprising computer program instructions capable of:receiving, by a system administrative component from the pluggableprocessing consumer component, the receipt indicating that the pluggableprocessing consumer component received the data; sending, by the systemadministrative component to the pluggable processing provider component,the receipt indicating that the pluggable processing consumer componentreceived the data; receiving, by the pluggable processing providercomponent from the system administrative component, the receiptindicating that the pluggable processing consumer component received thedata; and administering, by the pluggable processing provider component,the data in response to receiving the receipt.
 16. The computer programproduct of claim 13 further comprising computer program instructionscapable of: determining, by the pluggable processing provider component,that the pluggable processing provider component did not receive thereceipt within a predefined time period; and performing, by thepluggable processing provider component, one or more corrective actionsin response to not receiving the receipt within a predefined timeperiod.
 17. The computer program product of claim 13 wherein maintainingaccess to the data further comprises storing the data in computer memoryof the pluggable processing provider component.
 18. The computer programproduct of claim 13 wherein maintaining access to the data furthercomprises storing information used by the pluggable processing providercomponent to recreate the data.
 19. The computer program product ofclaim 13 wherein the computer readable medium comprises a recordablemedium.
 20. The computer program product of claim 13 wherein thecomputer readable medium comprises a transmission medium.